Is the stock D44 axle shafts strong enough to handle 37" tires? Jeep will mainly be a DD. Or would stronger shafts be needed? Thanks.

Just to clarify I am talking about the rear D44

 

C gusseted and sleeve and you will be fine.

 

As a daily driver sure. Any off roading should involve being cautious about the skinny peddle. I believe there are plenty of people running 37" tires on the D44 axles, several in our club that wheel hard. I wouldn't think twice about it, but being in the mid-west our wheeling does not involve rocks, just mud and hill climbs.

 

The shafts are strong enough. The problem with the shafts is that the c style u-joint clip can come off, which lets the u-joint cap come off. Then the u-joint binds, and breaks the ears on the axle shaft. Other parts of the axle are marginal in strength. The tubes and c-gussets are the same on the 44 as on the 30, and have been know to bend, or break.

There was a poll on one of the JK forums where they asked people if they had bent their front Dana 44 axle, or not. The last I saw the poll the score was 110 had not bent their axle, and 3 had bent their axle. I think the odds are pretty good that you will be ok.

 

Stock shafts are not the best. I swapped mine for Superiors and sleeved/gusseted my front D44.